Diaphragm pump



1951 J. E. N. YATES ETAL 2,

DIAPHRAGM PUMP Filed March 28, 1947 6 heet -Sheet 1 MM, .6 42/, fiffi am I 7 wart gwdwm 1951 J. E. N. YATES ET AL 2,542,786

DIAPHRAGM PUMP Filed March 28, 1947 6 s-Sheet 2 yaw/ w a a b 2 m M q. & m M? .VM EEQE=====z. 1 11 b e i mmmmuw n u 7 31 fl 4 7 m 3 V ////7/// AVFMMMLJIIHIWW 4 O4 1 j j g J. E. N. YATES ETAL DIAPHRAGM PUMP w u r r ...s. m

Feb. 20, 1951 Flled March 28, 1947 Feb. 20, 1951 J. 5. N. YATES ET AL 2,542,786

DIAPHRAGM PUMP Filed March 28, 1947 V 6 Sheets-Sheet 5 yww Feb. 20, 1951 J- E. N. YATES ETAL 2,542,786

DIAPHRAGM PUMP Filed March 28, 1947 6 Sheets-Sheet 6 wax QZWQ/WM Eatentecl Feb. 20, 1951 UNITED STATES PATENT OFFICE DIAPHRAGM PUMP Application March 28, 1947, Serial No. 760,674 In Great Britain March 29, 1946 1 Claim.

This invention consists in a new or improved diaphragm pump and is particularly, but not exclusively, concerned with the provision of a pump suitable for use with beverages such as beer and milk or other liquids which require a high degree of cleanliness in the pump and freedom from contamination by lubricants.

The invention provides a diaphragm pump comprising a casing in which are formed two opposed pump chambers provided with automatic inlet and outlet valves, two opposed pistons arranged for reciprocation in guides formed in the casing and appropriated to the two pump chambers respectively, two flexible pump diaphragms arranged for reciprocatory pumping operation by the two pistons respectively and each forming a wall or part of a wall of the pump chamber to which the associated operating piston is appropriated, and an operating eccentric or crank common to the two pistons and arranged on rotation to reciprocate the two pistons and their respective diaphragms in out of phase relationship. In one construction according to the invention, the two pistons are integral with one another or are connected together and reciprocate as a unit.

In the preferred form of the pump according to the invention, there is a resilient link in the operative connections between each diaphragm and the eccentric or crank whereby when a predetermined pressure is reached in the pump chamber the displacement of the crank or eccentric is absorbed in the resilient link and the pumping stroke of the diaphragm is reduced or eliminated. Conveniently, each piston is divided in its length and a compression spring tending to separate the two parts of the piston forms the resilient link.

According to a preferred feature of the pump the valves are of the type comprising a rigid perforated seating and a flexible disc overlying the perforations and secured at its centre to the seating by means which permit the outer portions of the disc to lift off the seating under fluid pressure to allow fluid to flow through the perforations. Transparent inspection windows covering the valves may be provided and the windows may be arranged for ready removal to provide access to the valves for cleaning.

a specific form of pump and some modified arrangements thereof embodying the above and other features of the invention will now be described, by way of example, and with reference to the accompanying drawings in which:

Figure 1 is an elevation showing the pump and driving motor Figure 2 is a side view of the pump and motor shown in Figure 1 Figure 3 is a section through the pump on the line 3-3 in Figure 2.

Figure 4 is a part section on the line 4-4 in Figure 3 Figure 5 is a view similar to Figure 2 of a modi fied construction Figure 6 is a view similar to Figure 1 but showing a further modified construction and Figure '7 is a side view of part of the construction shown in Figure 6.

The pump shown in Figures 1-4 is intended for dispensing beer through one or more servicing points at which measuring devices are provided and is arranged to be driven by an electric motor. The pump l and motor 2 are constructed as a unit and when in the operative position the pump is mounted above the motor with the axis of the pump and motor shafts extending vertically as shown in Figures 1 and 2. There are two drip-trays 3 between the pump and the motor arranged to collect drips from the pump during cleaning and prevent them seeping into the motor. The pump casing consists of a casting 4 having a vertical passage 5 provided with suitable bearings 6, 1 for the pumpshaft 8 and a horizontal cylindrical passage 9 which constitute cylinders for the pistons [3. Attached to the pump casing at each end of the horizontal throughway 9 there are units [0 constituting the pump chambers and valve chests. The pump shaft 8 has an eccentric I I at a position centrally in the bore of the horizontal passage 9 and there is a ball bearing l2 surrounding the eccentric.

The pistons l3 are positioned in the cylinders one to each side of the pump shaft and each piston has a follower l4 continuously engaging the periphery of the ball bearing I! onthe eccentric. Each piston is divided into two parts [3a, l3b in its length and the two inner parts I3a are connected together by screws I5 (Figure 4) to form a unit surrounding the pump shaft. Each inner 13:: part has an upstanding peripheral flange l6 bearing against the cylinder wall and an upstanding central boss ll within which the associated follower i4 is screwed. The follower has an enlarged head I8 of greater diameter than the boss [1. The portion I32) of each piston, herein referred to as the piston body, is of annular form and of substantially channel cross-section, the mouth of the channel l9 facing towards the inner portion of the piston. One arm of the channel section, the outer arm 20 constitutes a cylindrical skirt bearing against the wall of the cylinder. The inner arm 2| surrounds and has a bearing on the upstanding central boss I? of the inner portion of the piston. There are two compressionsprings 2-2, 23 extending between the two-portions of thepis: ton and retained within the outer flanged pore tions l6 and 20 thereof. These springs tend to separate the two portions of the piston and the movement of separation is limited-by engage-.- ment of the enlarged head I8 of the iollower with the piston body. A rubber bufier Hiais interposed between the head l8 and'the piston body to reduce the shock of the re-engagement between these two parts when, as later described, he ariss nar te te reduc he re ecti e strok the mime-L ttac ed e c is ody wer a fiqxi di pb ta m 2 t i phra m bein held in, position by screwsv 26. passing hrou a i te dfl T p st hea 21 is in the form of a metal disc and there. may be a. sheet metal cover (not shown) sprung: over the disc to prevent an accumulation of dirt inthe. screw heads, and. to. present. a clean smooth surface forwiping. The outer periphery of each f. e. d aph a m 25 sclem ed a ains h en of the pump casing by one of'the pump chamber un t l rer euslrrefe ed o,

Each pump chamber unit It is in two parts We. b. The rt ite-i m t rm, o an ann a ring with two, radiai extensions 30, 3L about 120 apart. Figure l). The. ring portion, constitutes an extension of the cylinder, of the pump and erns ar fih -pu n hembe pertof he tt e edgt heeumnc ine b mp: s. b lts 2.. minu e 3- iwhi hb s ar also P. 9Y s at r de ib d, in nencl e r W ure. h other P r W of he-unit The n rt en. e v ql p he as ocia e dia h .5; a ain t t nd. Q J H me in e Each ater ex ensio i i as a maq inedpa saee e iend ne rall l 9 th a i Q h pumn cyl inder andone of th se, pa sages. fits over; onee'nd iithe. ross-pie e L TOf a -s ape s pp y.- ine. 31 (Figure. 1') common to. both pump. cylinders and h o he s ge fi s. or ro e en f the ros tta .8. f, a. ha ehar p ns 3. mmo tothetwo cylinders. (Figure 3.). I

Thepartj I01), of the pump chamber unit constitutes. the cylinder head and has similar inlet and outlet valve ports. in the head, each portconsiste ee i a l s. 10 ma hi e e hea Qn the outside, of the head there is an upstand-.. hollow bossj 4i machined internally, providing two, separated cylindrical. chambers 42, 43. coaxiel with the two, rings: of valve. holes. The head has two radial extensions 413,45. corresponding tothe extensions, 3.0, 31 on the ring Um as described, above. and providin passage connecting the inlet and outlet valve. ports with the supply anddis: charge pipes. It and 3.9. through. the chambers 42. nd is .iesn ct r T e heads sec r d o the pilnmcasiris by m n of e, la ping. l s 2 described above which are. extended to pass. thrdugh the ead, a dprqvidr-e. ith: fing r.

4; 46 on their outer ends. The head has a spigot 41 fitting into the ring portion of th other part Illa and a sealing ring 48 located between the two parts serves to prevent leakage of fluid from the joint. Sealing rings @9 are also provided around the cross-pieces of the inlet and discharge pipes where they pass through the aforesaid passage and these rings are clamped between recessed faces 5G, 5!, on the two parts of the unit, the faces being tapered to clamp the rings against the cross-pieces of the pipes. In this way, leakage of fluid along the outside of the pipes is prevented while at the same time a limited freedom of adjusting movement of the pipes during the erection of the apparatus is permitted.

The valves each consist of a flexible disc a, 55b of non-fabric synthetic material suitable for use. with beercovering the ports 4|] in the cylinder head and each disc is retained in position by a central boltifi passing through the head and secured by a lock nut. The bolt has an enlargement 51 (gr-conical form which serves to limit the flexing movement of the valve disc 55. The inlet valve; disc 55a is located on the inside of the head, and the outlet valve disc 55b is located on the outside o.f the head. F 1- G se of manufacture the heads appropriate to the two cylinders of the pump may bev made interchangeableand for this.

purpose, both sides of each ofthe valveportsrnay be machined to serve'asvalve' sQa-ts. Access to the valves may be obtained tln oilgh. suitablefaper tures in the boss on the cylinder head, these apertures. being closed in use by means, oi caps-58 which y e c s r t of ra s n mate rial or include transparent windows.

In the construction described above, the inlet: and outlet valves. lie within the circumference of V the cylinder heads and it will be appreciated that. by removal of the heads. ready access may be ob.- tained. to the valves, the faces of the pump. diaphragms and to the cross-pieces of the inlet and discharge pipesv for cleaning purposes.

In addition tov the. clamping bolts 32 described above for securing the two. parts of the pump chamber unit. together and for securing-the tothe pump casing, further clamping devices mattbe. provided if; considered necessary for securing the lateral. extensions of the-two parts tegether. These members may. consistiof bolts pivotally securedto, the. head and engaging in forked lugs.

provided on the other part at the ends of the eX-. Y tensions.

i d s d, a e i n m y b made tc he let sideoi thepump. (e. g. at thaintersection-Bll, of the cross-piece and upright portions. of. the inlet. Tepiece) for the purpose offacilitating the: prime ing of the pump. The connection may be pro;. vided with a valve. or cook and when it is desired to prime. the puma. the cock is openeduand cone nectionmade with a small, supply of the fluid which is drawn into the, inlet system of; the and is; found in practiceto prime this part of the, system. This arrangement may beused, with or withQuta foot-valve.

A c onneqtion. may also. be, made to the. inlet side oi thepump'for the recovery of waste flu-id.- Thus when thepump is to. be used for beer, any beer.- spilt at. the dispensing head is collected and fed into the inlet of the pump. through theaforesaid,

connection and. is reecirculated.

As alreadystated the pump. is mounted v r-.. tically upon an electric driving motor and it is driven by. the. motor operating through a reduction gear within the casing. 65. provided by the. mo or n can. If desir d. h summer be ei- 'rectly coupled to the motor, i. e. without a reduction gear. With a view to standardising the castings required to enable the pump to be driven directly or at a reduced speed, as may be necessary to obtain the required pump out-put, the motor end cap is provided with a suitable boss for the reception of a spindle supporting a driven gear andthe pump base is arranged for attachment to the motor end cover in either of two positions corresponding respectively to a direct drive and to an indirect drive through a gear Su ported on the boss aforesaid.

the operation of the pump so long asbeer is being delivered the two diaphragm complete their full stroke at each revolution of the pump shaft. When the delivery cock is closed and pressure built up in the delivery system the resistance to movement of the diaphragms causes the springs in the pistons to collapse reducing or eliminating the effective stroke of the diaphragms Without causing undue strain upon the driving mechanism. The pump therefore has the advantage that it may be run continuously and is capable of maintaining a constant substantially non-pulsating pressure in the supply line so that beer may be Withdrawn at any time and there is little or no agitation of the beer while the pump is idling. It is a further advantage of the pump that by reason of its robust construction and the provision of cylindrical pistons and co-operating cylinders it may be run continuously without attention. The pump may be incorporated in an existing beer delivery system if desired and the whole system may be sealed against ingress of air.

The pump may be arranged for remote control by an electric switch which may embody a pilot light and a thermal overload, and the pump may be situated at any convenient position from which it can supply several spaced delivery points.

The use of flexible pumping diaphragms and valves ensures that the pump will make the minimum of noise when running. In order further to reduce the noise, the pump and motor unit may be enclosed in a sound-proof box.

The materials used in the construction of the pump are chosen with regard to the particular fluid to be pumped, and the fluid chambers are machined internally throughout. The materials may, for example, be stainless steel, anodically treated aluminum or nickel plated brass.

Figure 5 of the drawings shows a modified arrangement of pump and motor unit in which two pumps I! as described above are driven by a single motor I02. Each pump is constructed as described above and the two pumps have independent suction pipes 3! and delivery pipes 39. The pumps may therefore be employed to deliver different beers or they may be used independently to deliver the same beer. On the other hand, if desired in any particular installation, the two pumps may be connected to a common suction line or a common delivery line or both. The pumps are driven from the motor through reduction gearing. The motor shaft has a gear I03 which engages with gears I04 on the two pump shafts, respectively, all these gears being located in a casing I05. The casing I05 is constituted in part by the motor end cover I06 and in part by a separate casting I01 having upstanding brackets I08 to which the pumps are attached.

Figures 6 and 7 show an alternative construction in which a single pump is employed. In this construction the pump has independent suction and delivery pipes I31 and I39 for the 6. two cylinders. The pump may therefore be em: ployed to deliver two different beers, or by connecting the suction pipes to a common source both cylinders may be arranged to deliver the same beer. In order to reduce pulsation from the two independent cylinders air bottles I I12 are provided in the delivery pipes adjacent to the pump outlets. These bottles are held by a clamp II 3 common to the'two bottles. The drip trays are omitted in. this example and drain cocks II4 are provided in the pump outlets to enable the outlet pipes to be drained into a suitable receiver before the pump is dismantled for cleaning or other purposes. The six finger nuts 46 employed in the previous constructions are, in this examplef replaced by three wing nuts I46. It is however to be noted that six bolts 32 and I32 are employed to clamp the parts I00, and I0b together.

Figure 6 is partly broken away to show a flexible coupling between the pump shaft 8 and the driving spindle I 20 of the gear I04. This coupling comprises a flange I2I pinned to the shaft 8, a flange I 22 pinned to the spindle I20 and a flexible rubber driving member I23 bonded to the two flanges. If it should be desired to remove the pump (e. g. for repair or interchange) the upper pin I24 is knocked out enabling the shaft 8 to be withdrawn from the coupling.

If desired the construction shown in Figures 6 and 7 may be modified by the addition of a second pump in the manner shown in. Figure 5. This second pump may be a duplicate of that shown and have independent suction and delivery pipes in which case the combined pump unit may be employed to pump four different types of beer. Alternatively the two pumps may each have suction and delivery connections common to the two cylinders in which case the air bottles may be omitted and the unit may be used to pump two different beers.

It is to be understood that the combined resistance to compression required of the springs 22 and 23 will vary according to the pressure at which the pump is required to operate. Conveniently, sets of interchangeable springs of different compression resistances are prepared for use in different pump installations.

As an alternative of the arrangements described in the above specific examples the motor and pump or pumps may be arranged horizontally. It is preferred to employ a standard synchronous motor for driving the pump.

We claim:

A diaphragm pump comprising a casing, two opposed pump chambers formed in said casing, automatic inlet and outlet valves in the two said chambers, suction and delivery means connected to the two said chambers through the said inlet and said outlet valves respectively, a piston divided in its length into three parts to comprise an inner part and two outer parts, a piston guide formed in said casing, each of the three parts of said piston being supported in and guided for reciprocation'in said guide, an operating eccentric connected with and arranged on rotation to reciprocate the inner part of said piston, an enlarged head portion provided on each end of the said inner part of the piston and arranged to ensage and move inwardly each of the outer parts thereof, respectively, on alternate strokes, spring means mounted between the inner part of the piston and the outer parts thereof, for moving the last named parts outwardly, respectively, on the intervening strokes of the said inner part, whereby the outer parts are moved inwardly solely by the: act's'ien; of; the vsaid head por ns andi out? wardly solelyvby'r the. action of thegslalifdiysprih i means; twoyflexible pump diaphragms each farminga-.. partof the; walls of one at the. said pump chambers, andirespeetively. connected with and. 5;,

arranged for reciprocatory pumtn'ng Qpemtion with the two said outer rmute of vthe pis on.

JOHN- ERNEST NEVILLE YATES. ARTHUR. LIONEL. BROWN DAWSON. GEORGE. CHARLES MEREDEW,

REFIEZRENC1115.

V The fellowing; references are of record in the fife of this patent:

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